Are you sure about the paypal in europe? AFAIK you can set it up Stripe only if your country supports Stripe which most of EU does.
I couldn't see any backend option to select the preferred Shopify Payments backend processor, but would be interested if you have insight into how to achieve this.
In what gives weight to the GP, we enabled Shopify Payments, confirmed it went through PayPal and switched back to Stripe to avoid the "process with PP for a week and then have them freeze your funds for 6 months" grind.